The AIDS Clinical Trials Unit (CTU) and Virology Support Laboratory (VSL) at Stanford University have been affiliated with the AIDS Clinical Trials Group since its inception in 1987 and has enrolled well over 1000 patients into ACTG trials. During this time Stanford investigators have served in man> different leadership capacities within the ACTG and have made significant contributions to the treatment of HIV infection through these efforts. Our CTU investigators and staff are now poised to build on this record cf scientific contribution within the context of the restructured clinical trials network. The Stanford CTU focuses primarily on the development, evaluation and optimization of combination antiretroviral drug therapy (ART) for the treatment and long-term management of HIV-1 infection including the use of novel agents and technologies for monitoring treatment efficacy. Our group has a particular interest in the basic mechanisms and clinical implications of drug resistance in HIV-1. The Stanford VSL is focused on drug resistance and subtype diversity of non-clade B isolates and has been designated as the drug resistance reference testing laboratory in the International-ACTG and ACTG network application. In addition, the Stanford group has developed a database which links HIV treatment histories and treatment outcomes to genotypic and phenotypic drug resistance patterns. Advanced informatics databases that manage high-dimensional data- like drug resistance data and pharmacogenomics data will likely become increasingly important resources for our understanding of the determinates of health and disease, response to treatment and risk of drug toxicities as we move forward in the next 5-10 years. The Stanford CTU comprises three Clinical Research sites with ethnically and socially diverse patient populations: (i) Stanford University's Positive Care Clinic in Palo Alto, (ii) The PACE Clinic at Santa Clara Valley Medical Center in central San Jose, and (iii) The Edison Clinic, run by the San Mateo County AIDS Program at San Mateo Medical Center. Through this constellation of sites we have always exceeded our community-based targets for under represented ethnic groups and women in ACTG trial enrollment. Although this working arrangement has been successful for over 10 years, further consolidations and streamlining described here will ensure that the proposed CTU and CRSs will be even more efficient. ADMINISTRATIVE COMPONENT: